by Mrs. Clementine Ortiz
Published 3 years ago
Updated 2 years ago
—FFE = fast field echo, FIESTA = fast imaging employing steady-state acquisition, FISP = fast imaging with steady-state precession, FLASH = fast low-angle shot, GRASS = gradient-recalled acquisition in the steady state, MPGR = multiplanar gradient-recalled, SPGR = spoiled gradient-recalled, SSFP = steady-state free ...Jul 1, 2008
What is balanced FFE MRI?
Jan 10, 2020 · What is FFE MRI? Fast Field Echo. (FFE) An echo signal generated from a FID by means of a bipolar switched magnetic gradient.
What is a FFE Echo in MRI?
(bFFE) A FFE sequence using a balanced gradient waveform. A balanced sequence starts out with a RF pulse of 90° or less and the spins in the steady state. Before the next TR in the slice phase and frequency encoding , gradients are balanced so their net value is zero.
What is FSE/TSE used for in MR imaging?
What is a fiesta MRI sequence? FIESTA (Fast Imaging Employing Steady-state Acquisition) is the GE name for a balanced steady-state gradient echo sequence that Siemens calls TrueFISP and Philips calls balanced-FFE.
What does SSFP stand for in MRI?
FFE GRE GRE GE FE Spoiled GE: T 1-FFE FLASH SPGR MPSPGR RSSG RF-spoiled FE Ultra fast GE: T 1-TFE T 2-TFE . THRIVE . TurboFLASH . VIBE. FGRE Fast SPGR FMPSPGR VIBRANT FAME LAVA SARGE Fast FE . RADIANCE QUICK 3D. Ultrafast GE with magnetization preparation: IR-TFE T 1 /T 2-TurboFLASH IR-FSPGR DE-FSPGR Fast FE Steady state GE : FFE FISP MPGR, GRE
What is balanced gradient echo?
"Balanced" means that the net gradient-induced dephasing over a TR interval is zero. Conversely, some of the gradients in FISP and PSIF are unbalanced, allowing recording of separate FID and echo components of the steady-state free precession signal.
What is spoiled gradient echo?
Spoiled gradient echo MRI (also known as incoherent gradient echo) is an MRI technique which destroys residual transverse magnetization at the end of each excitation cycle.Apr 2, 2020
What is steady state sequence?
Steady-state sequences are a class of rapid magnetic resonance (MR) imaging techniques based on fast gradient-echo acquisitions in which both longitudinal magnetization (LM) and transverse magnetization (TM) are kept constant.
What is the difference between spin echo and gradient echo?
How does a gradient echo differ from a spin echo? A spin echo (SE) is produced by pairs of radiofrequency (RF) pulses, whereas a gradient echo (GRE) is produced by a single RF pulse in conjunction with a gradient reversal.
The most common MRI sequences are T1-weighted and T2-weighted scans. T1-weighted images are produced by using short TE and TR times. The contrast and brightness of the image are predominately determined by T1 properties of tissue. Conversely, T2-weighted images are produced by using longer TE and TR times.
What is CISS sequence in MRI?
Three-dimensional (3D) constructive interference in steady state (CISS) is a fully refocused steady-state gradient-echo MRI sequence. This sequence is now freely available and is frequently used in MRI to investigate a wide range of pathologies when routine MRI sequences do not provide the desired anatomic information.
How can I tell what sequence my MRI is?
The best way to tell the two apart is to look at the grey-white matter. T1 sequences will have grey matter being darker than white matter. T2 weighted sequences, whether fluid attenuated or not, will have white matter being darker than grey matter.Jun 4, 2015
What is spin-echo sequence?
The spin echo sequence is made up of a series of events : 90° pulse – 180° rephasing pulse at TE/2 – signal reading at TE. This series is repeated at each time interval TR (Repetition time). With each repetition, a k-space line is filled, thanks to a different phase encoding.
Why are RF pulses used in MRI?
RF pulse is applied for a few milliseconds disturbs or flips the protons at the same time and out of alignment from the main magnetic field. The amount of this rotation or flip depends on the strength and duration of the RF pulse. 90 RF pulse rotates the net magnetization vector to transverse plane .Nov 5, 2021
What is the difference between T2 and T2 *?
T2* can be considered an "observed" or "effective" T2, whereas the first T2 can be considered the "natural" or "true" T2 of the tissue being imaged. T2* is always less than or equal to T2. T2* results principally from inhomogeneities in the main magnetic field.
What is flair in brain MRI?
Fluid-attenuated inversion recovery (FLAIR) is an MRI technique that shows areas of tissue T2 prolongation as bright while suppressing (darkening) cerebrospinal fluid (CSF) signal, thus clearly revealing lesions in proximity to CSF, such as cerebral cortical lesions.
What is contrast enhanced MRA?
Unlike conventional MRA techniques based on velocity dependent inflow or phase shift techniques, contrast enhanced MRA exploits the gadolinium induced T1-shortening e ffe cts. CE MRA reduces or eliminates most of the artifacts of time of flight angiography or phase contrast angiography. Advantages are the possibility of in plane imaging of the blood vessels, which allows to examine large parts in a short time and high resolution scans in one breath hold. CE MRA has found a wide acceptance in the clinical routine, caused by the advantages:
What is CE MRA?
CE MRA reduces or eliminates most of the artifacts of time of flight angiography or phase contrast angiography. Advantages are the possibility of in plane imaging of the blood vessels, which allows to examine large parts in a short time and high resolution scans in one breath hold.
Is T2 weighted gradient echo EPI fast enough to capture the three-dimensional nature of activated brain
By using T2 weighted gradient echo EPI sequence s , which are highly susceptibility sensitive and fast enough to capture the three-dimensional nature of activated brain areas will show an increase in signal intensity as oxyhaemoglob in is diamagnetic and deoxyhaemo globin is paramagnetic. Other MR pulse sequence s, such as spoiled gradient echo pulse sequence s are also used.
What is a flash MRI?
Fast low angle shot (FLASH) is the most commonly used gradient spoiled gradient-echo MRI-sequence in abdominal imaging. FLASH uses radio frequency excitation pulses with a low flip angle (less than 90 degrees) and subsequent reading gradient reversal for producing a gradient echo signal. The small flip angle pulses create equilibrium of longitudinal magnetization. Transverse magnetization is eliminated by a strong gradient (spoiler gradient). T1-weighted and T2*-weighted contrast can be set with the FLASH sequence.
What is the difference between vibe and flash?
VIBE and FLASH sequences look similar, the only noticeable difference is FLASH sequences have low SNR compare to VIBE (i.e. VIBE is brighter than FLASH ). Tissues and their T1 FLASH appearance. Bone marrow : - equal to or higher than that of muscle (fatty marrow is usually bright)
What sampling strategies can be used with FSE?
Although the pulse diagram above and later discussion are focused on a Cartesian/rectilinear trajectory, FSE/TSE can be used with virtually all k -space sampling strategies, including spiral, radial, circular, and PROPELLER methods.
What is a fast spin echo?
Fast spin echo (FSE) imaging, also known as Turbo spin echo (TSE) imaging, are commercial implementations of the RARE ( R apid A cquisition with R elaxation E nhancement) technique originally described by Hennig et al in 1986. Since that time FSE/TSE has grown to become one of the "workhorse" pulse sequences used in virtually all aspects of modern MR imaging.
Can FSE be used in 3D?
FSE/TSE can be used in either 2D or 3D mode. In 2D acquisition, multiple slices are nearly always interleaved because the TR is generally longer than the sequence length. The time savings afforded by the FSE/TSE technique has made 3D acquisition realistically possible for the first time. In the FSE/TSE pulse sequence diagram above you will note ...
Is FSE superior to CSE?
Finally, susceptibility-induced signal losses are reduced, making FSE superior to CSE for imaging the skull base and around metal objects. Reduction of magnetic susceptibility artifacts may be disadvantageous, however, as FSE images are less likely to detect small areas of calcification or hemorrhage.
23 hours ago
Jan 10, 2020 · What is FFE MRI? Fast Field Echo. (FFE) An echo signal generated from a FID by means of a bipolar switched magnetic gradient.
1 hours ago
(bFFE) A FFE sequence using a balanced gradient waveform. A balanced sequence starts out with a RF pulse of 90° or less and the spins in the steady state. Before the next TR in the slice phase and frequency encoding , gradients are balanced so their net value is zero.
14 hours ago
What is a fiesta MRI sequence? FIESTA (Fast Imaging Employing Steady-state Acquisition) is the GE name for a balanced steady-state gradient echo sequence that Siemens calls TrueFISP and Philips calls balanced-FFE.
4.Fast Field Echo imaging: an overview and contrast …
Url:https://pubmed.ncbi.nlm.nih.gov/3054380/
28 hours ago
FFE GRE GRE GE FE Spoiled GE: T 1-FFE FLASH SPGR MPSPGR RSSG RF-spoiled FE Ultra fast GE: T 1-TFE T 2-TFE . THRIVE . TurboFLASH . VIBE. FGRE Fast SPGR FMPSPGR VIBRANT FAME LAVA SARGE Fast FE . RADIANCE QUICK 3D. Ultrafast GE with magnetization preparation: IR-TFE T 1 /T 2-TurboFLASH IR-FSPGR DE-FSPGR Fast FE Steady state GE : FFE FISP MPGR, GRE
23 hours ago
Fast low angle shot (FLASH) is the most commonly used gradient spoiled gradient-echo MRI-sequence in abdominal imaging. FLASH uses radio frequency excitation pulses with a low flip angle (less than 90 degrees) and subsequent reading gradient reversal for producing a gradient echo signal. The small flip angle pulses create equilibrium of longitudinal magnetization.
